The present invention is directed to integrated circuits and their processing for the manufacture of semiconductor devices. More particularly, the invention provides a method and device for manufacturing a mask structure including an anti-static device and a related integrated circuit device. Merely by way of example, the invention has been applied to guard ring structure on the mask structure for advanced integrated circuit devices for critical masking steps. But it would be recognized that the invention has a much broader range of applicability. For example, the invention can be applied to non-critical steps as well, as well as various interconnect structures.
Integrated circuits or “ICs” have evolved from a handful of interconnected devices fabricated on a single chip of silicon to millions of devices. Current ICs provide performance and complexity far beyond what was originally imagined. In order to achieve improvements in complexity and circuit density (i.e., the number of devices capable of being packed onto a given chip area), the size of the smallest device feature, also known as the device “geometry”, has become smaller with each generation of ICs. Semiconductor devices are now being fabricated with features less than a quarter of a micron across.
Increasing circuit density has not only improved the complexity and performance of ICs but has also provided lower cost parts to the consumer. An IC fabrication facility can cost hundreds of millions, or even billions, of dollars. Each fabrication facility will have a certain throughput of wafers, and each wafer will have a certain number of ICs on it. Therefore, by making the individual devices of an IC smaller, more devices may be fabricated on each wafer, thus increasing the output of the fabrication facility. Making devices smaller is very challenging, as each process used in IC fabrication has a limit. That is to say, a given process typically only works down to a certain feature size, and then either the process or the device layout needs to be changed. An example of such a limit is the ability to form smaller and finer patterns with mask structures. Such mask structures often accumulate static charge that discharge onto the smaller patterns to cause damage on them. Damaged masks transfer damaged patterns onto integrated circuits, which lead to device failures and reliability problems.
Often times, damaged masks are caused by electrostatic discharge problems from charge that accumulates on the active region of the masks. Static charge builds up builds up to thousands of volts, which discharge from one region of the mask onto another region to cause damage to the mask. Many attempts have been made to limit such static discharge. As merely an example, ionizers have been used to remove static charge from the masks. Other techniques include applying electrostatic discharge materials on working surfaces of clean rooms, etc. that are used during the manufacture of integrated circuits with the masks. Unfortunately, human operators still handle the masks, which cause damage to the masks themselves. Such masks often cost tens of thousands of dollars and often require a long lead-time to receive from a vendor of the mask. Accordingly, there are many limitations with conventional masks and their use in the manufacture of integrated circuits.
From the above, it is seen that an improved technique for processing semiconductor devices including photo masks is desired.